ES2584608T3 - Tool holder - Google Patents

Abstract

The tool-holder device comprises clamping means (4) for clamping a tool (24), a movable part (2) that can move in the axial direction and a pneumatic mechanism (3) that can induce an axial vibratory movement to the movable part (2 ). The clamping means (4) are coupled to the moving part so that the axial vibratory movement of the moving part (2) is transmitted to the tool (24).

Description

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DESCRIPTION

Tool holder device Object of the invention

The present invention has application in the field of parts machining operations, in particular to the drilling operation, and refers to a tool holder device according to the preamble of claim 1, attachable to a machine or equipment by means of an axis Machining or mooring cone.

More specifically, the object proposed by the invention allows to produce an axial vibratory movement with respect to the linear movement of the machine and transmit it to the tool with rotation. An exemplary tool holder is known from FR2 368 336 A1.

Background of the invention

Currently, within the field of machining, the drilling and deep drilling process are very important machining operations in various sectors of the industry, and despite being a technology that is in its maturity period, the appearance of new materials, tools, lubricants, machines, controls, etc., open a very extensive field of study to meet the demands of productivity and the environmental legislation of the market.

The current problems of drilling are linked to productivity and surface and / or dimensional quality to be obtained.

Typical problems such as the generation of long and rolled shavings during the drilling of ductile materials and the appearance of unwanted vibrations, are examples of phenomena to improve in the machining of high productivity of industrial components, since they involve an increase in unproductive time, also leading to losses due to the manufacture of defective parts and even breakdowns in the machines, so that the elimination of delamination, reduction of the burr, reduction of the cutting temperature and improvement of the roughness in the drilling of Aeronautical materials are objectives of great interest to companies in the sector.

The application of vibrations during manufacturing processes such as machining, welding or forming is a relatively common practice in research and industry for the solution of problems related to conventional manufacturing methods.

Within the field of drilling, the application of an axial vibratory movement relative to the linear movement allows reducing the problems mentioned above, as it can reduce the energy required to perform the operation, increase productivity, facilitate chip breakage, extend the life of the tools, increase the superficial and internal quality and allow to work materials not apt to be processed in a conventional way.

There are currently inventions that allow this process to be developed, known as vibration-assisted drilling.

Said inventions can be classified according to the place where the vibration is applied, being, in the first place, the devices that obtain the vibration in the tool without this turning, secondly, the devices that make the piece vibrate or test tube to be drilled, and finally there are devices in which the tool rotates and vibrates simultaneously, a group in which the present invention is included.

Within this last class of tool holders is document US 6234728 (B1), which includes a mounting accessory for a drilling tool that has a coupling support to the machine, a tool holder for fixing the tool that moves forward and backward by means of a axial guidance relative to the support and which rotates jointly with the tool holder, and which is composed of suspension means in the axial direction to produce axial vibratory movements in the tool holder as a result of a controlled displacement of the support with respect to the workpiece.

In the application of vibrations during drilling, two factors to control, frequency and amplitude are fundamentally involved. Depending on the tool, the material and the type of hole to be drilled, the parameters of the tool tip vibration vary, so there is a need to be able to modify both the frequency and amplitude of the vibration.

Said vibration is applied in the axial direction of the tool following a sinusoidal pattern and amplitude greater than the advance per edge, which causes an interruption of the cut. By varying the frequency and amplitude of the cut, the value of the average chip thickness increases or decreases, so it is necessary to be able to modify it according to the needs of each type of drilling.

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In addition, in the drilling of some materials such as compounds, the value of the amplitude of the vibration is an important parameter to control since not very high amplitudes are needed at the exit of the hole due to the possible delamination of the fibers.

On the other hand, in drilling operations it is usually very common to perform other operations such as countersinking of the holes, for which the application of vibrations is not necessary.

In the invention with reference US 6234728 (B1), there is a problem that said toolholder generates the vibrations through the contact between the tool and the workpiece so that the frequency and vibration parameters are given for each case without the option of modifying said parameters.

In addition, in case of doing some type of operation in which vibrations are not required, such as during the countersinking of a hole, said toolholder would not be worth it and would have to be changed for another to perform the operation with absence of vibrations.

The present invention is based on the problem of providing a tool holder that is designed for the application of low frequency vibrations in which the characteristics of the vibration can be varied as the amplitude depending on the drilling needs and the possibility of being able to select vibrations without changing the tool holder in operations that do not require vibrations at the tool tip.

Description of the invention

The present invention relates to a tool-holder device that overcomes the aforementioned drawbacks, since it has a body that can be attached to a machine by means of a mooring cone and a pneumatic mechanism that allows the axial vibratory movement of the tool to be produced with respect to the controlled linear movement the machine and in which it is possible to control the amplitude of the vibrations.

It is also possible to deactivate the state of the vibrations without changing tool holders for cases where it is not appropriate to work in that state, so it could be used to perform different operations with the same tool holder device.

Specifically, the tool holder device is attachable to a machine that can produce the rotation of the tool holder device (with respect to an axial direction of the tool) and comprises fastening means for holding a tool. The device comprises a mobile part that can move in the axial direction and a pneumatic mechanism, where said pneumatic mechanism can induce an axial vibratory movement to the mobile part, and by which the fastening means are coupled to the mobile part. In this way, the axial vibratory movement of the mobile part is transmitted to the tool.

The pneumatic mechanism comprises a pneumatic piston that makes a linear movement in two directions of the axial direction, to generate vibrations in a simple way.

The mobile part of the tool-holder device comprises a chamber that houses the pneumatic piston so that it can slide axially inside the chamber and conduction means that allow pressure air to be taken to internal ducts that cross the piston and open in the chamber on axially opposite faces of the pneumatic piston, thus producing its oscillating movement that causes the piston to alternately collide with the inner walls of the chamber of the mobile part, causing a similar oscillatory movement of the mobile part and, therefore, of the tool tied to the mobile part.

The tool holder device comprises a body comprising a mooring element that allows the device to be coupled to the machine and a housing in which the movable part can be axially displaced. The body comprises a conduit that communicates a source of pressurized air supply of the machine with the conduction means of the mobile part. The body therefore exercises the functions of attachment to the machine where the device is attached and also houses the mobile part, which functions to tie the tool and make the entire device vibrate by means of an axial movement relative to the body.

The tool holder device can comprise a regulator that allows varying the amplitude of the axial movement of the mobile part and therefore provides the possibility of varying the amplitude of the vibrations adapting them to each case.

The regulator comprises a nut that engages on the body by closing the housing in a first direction according to the axial direction to stop the movement of the mobile part in the first direction, while in a second direction, according to the axial direction, the accommodation is closed and stops the movement by the body. The nut can vary its position in the axial direction by varying the axial length of the housing.

The regulator may comprise adjustment means that anchor the nut to the mobile part of the device to fix the position of said nut, in a simple and integrated manner.

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The possibility is contemplated that the device comprises a first buffer stop located inside the body housing so that the shock between the mobile part and the body is cushioned.

The possibility is contemplated that the device comprises a second buffer stop on the regulator to dampen the collision of the mobile part with the regulator.

Finally, the possibility is contemplated that the first and second damping stops are fixed to at least two opposite faces of the mobile part by means of fixing means, so that the clearance between damping stops is always referred to the body, thus enabling the Optimum variation of the amplitude of vibration through the regulator.

The possibility is contemplated that the body comprises means of union that join the mobile part to said body, so that they rotate in solidarity with the transmitted torque, and the vibration function with rotation is achieved, in the simplest possible way.

The possibility is contemplated that the pneumatic mechanism comprises return means (for example a spring housed in the chamber of the mobile part against which the pneumatic piston can collide), to facilitate the change of direction of the linear movement made by the piston.

The possibility is contemplated that the device comprises a sealing element between the body and the mobile part (so that the clearance between the body and the mobile part is sealed in at least one of its faces to prevent the escape of air intended to activate the pneumatic mechanism).

It is also contemplated that the device comprises an antifriction element (for example located between the external face of the mobile part and the fixed face of the body) for axial guidance between the mobile part and the body.

It also contemplates the possibility that the body comprises through silencer holes made in its surface (as valves) that expel the compressed air.

Thus, in accordance with the described invention, the implant proposed by the invention constitutes an advance in the fastening devices used up to now, and solves in a fully satisfactory manner the problematic described above, in the line of favoring drilling operations by means of Vibration of the tool, which is done in a simple way, with the consequent improvement of the manufacturing processes and with the consequent reduction of costs by the simplification of the process, all through a simple and integrated design, which does not require operators Highly qualified for the task.

Description of the drawings

To complement the description that is being made and in order to help a better understanding of the features of the invention, according to a preferred example of practical realization thereof, an set of drawings is accompanied as an integral part of said description. For illustrative purposes and not limitation, the following has been represented:

Figure 1 shows a perspective view of the device proposed by the invention.

Figure 2 shows a sectional view of the device, where its components can be seen, where the pneumatic mechanism can be seen in detail, with the piston in the upper position.

Figure 3 shows a sectional view of the device, with the piston in the lower position.

Figure 4 shows a sectional view of the device plan, where a detail of the keys can be seen.

Preferred Embodiment of the Invention

In view of the figures summarized, one of the possible embodiments of the invention can be seen a tool holder device comprising a body (1) and a mobile part (2), where the mobile part (2) comprises fastening means (4) of the tool (24), preferably a clamp that holds the tool (24), which is the object of the vibration of the invention, as can be seen in Figures 2, 3 and 4.

The body (1) comprises a mooring element (5), which is preferably a mooring cone or machined shaft, for coupling to a machine, and through which a turning movement is transmitted to the body (and therefore to the tool) and the pressurized air is transferred from the machine to the tool holder device. This pressurized air is necessary for the vibratory effect of the tool holder as explained below.

The body (1) comprises a housing in which the movable part (2) can be axially displaced. The mobile part (2), which is preferably a pin holder shaft, is formed by two parts, a first part (19) that has a duct (8) through which pressurized air enters from inside the mooring cone and a second part (20) to which the mooring means (4) of the tool (preferably a clamp clamp) are attached.

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The fixing between said first part (19) and a second part (20) of the movable part (2) or pinhole shaft, is preferably carried out by means of mooring screws along the contact area between them, so that the union of these parts forms the mobile part (2), as can be seen in figures 1,2, 3 and 4.

The mobile part (2) comprises a chamber (21) that houses a pneumatic piston (6) that generates the vibratory movement, specifically the second part (20) acts as a sleeve where said pneumatic piston (6) is guided.

The pneumatic piston (6) is the element in charge of generating the axial vibratory movement of the tool-holder device, and comprises distributor holes or internal ducts (22) that pass through the pneumatic piston (6) opening in the chamber (21) on axially opposite faces of the pneumatic piston (6) and therefore alternately distribute the pressurized air in the chamber (21) to produce the vibratory axial movement of the pneumatic piston (6).

The second part (20) comprises conduction means (23) that carry the pressurized air from the conduit (8) of the first part (19) to the distributor or internal orifice (22) of the piston (6).

The movement of the piston (6) is produced by the entry of air through the mooring cone, where the air is carried through the duct (8) communicated with internal ducts (22) that cross the piston (6), the which receive the air and that communicate with conduction means (23) that receive the air in an alternative way, thus allowing the alternate movement of the piston (6).

The two extreme positions of the piston (6) in its movement inside the axle holder are, on the one hand, the contact position with the first part (1) and on the other, with the inner face of the second part (20) of the axis holder, as can be seen in figures 2 and 3.

Inside the chamber (21) is housed a return means (12), which is preferably a spring or spring, which helps the movement of the piston (6), and where, in addition, the pin holder shaft (2) preferably comprises , two holes (17) which are preferably silencer holes, whose function is to give air to the system, as can be seen in figures 1,2, 3 and 4.

In the interface between the pin holder shaft (2) and the body (1) there is an anti-friction means (16), which is preferably a bronze bushing, for guiding the pin holder shaft (2), where said bronze bushing is internally fixed to the body (1), as can be seen in figures 2, 3 and 4.

In order to ensure that the rotation or rotation movement generated on the body (1) is effectively transferred to the tool through the pin holder shaft (2), joining means (9) have been placed, which are preferably three anti-rotation keys, so that the mobile part (2), preferably the pin holder shaft, rotates in solidarity with the body (1), as can be seen in figures 1,2, 3 and 4.

Each of the anti-rotation keys is preferably composed of two screws that are attached to the body (1) so that both the rotational movement and the axial vibratory of the piston (6) are transferred to the tool (24) through the shaft holder (2).

The tool holder device comprises a regulator (7) of axial movement amplitude, which is composed of a nut (14) and adjustment means (13) that are preferably asparagus, has the function of fixing the freedom of movement of the axle holder (2) inside the body (1), leaving more or less space to exercise the vibration with different amplitudes; where the nut (14) acts as a stop of the movement, and the studs are responsible for fixing the nut (14) on the body (1), and the space between the pin holder shaft (2) and the nut (14) can vary. .

The body (1) preferably has a nonius engraved on its outer surface that indicates the amplitude at all times and that facilitates the adjustment in case of modifying the required amplitude taking as reference the nut (14), as can be seen in the Figures 1,2, 3 and 4.

The type of vibrations of the present invention are considered low frequency (between 0 and 5000 Hz) depending on the size of the pneumatic actuator, the tool used, the material to be drilled, etc., and can be regulated, as indicated above, the amplitude of the vibrations by means of the regulator (7) of amplitude of the axial movement, adapting the device to the own needs of the process.

On the other hand, a first damping stop (10) and a second damping stop (11), which are preferably rubber stops, are arranged inside the body (1) to minimize the shock between the mobile part (2) and the body (1), for which there is a rubber stop attached to the first part (19) of the mobile part (2) by fixing means (18), which are preferably two screws, and another rubber stop tied to the second part (20) of the mobile part (2) preferably by two other screws.

The two rubber stops move in solidarity with the mobile part (2), where said mobile part (2) is abutting, on the one hand, with the inner face of the body, and on the other hand, with the inner face of the regulator ( 7) amplitude, which is what sets the clearance between the rubber stop and the amplitude regulator (7).

5 In turn, between the mooring cone and the individual part with the air inlet, there is a sealing element (15), which is preferably an annular gasket that acts as an air seal, so as to guide the entrance of the air to the pneumatic mechanism (3), as can be seen in figures 2, 3 and 4.

Overall, by means of the explanation described herein, a tool holder device 10 attachable to a machine is made possible, in which a drilling tool is moored, and which makes it possible to obtain vibratory movements thereof as it progresses, through a pneumatic mechanism, where the air inlet is made through the coupling with the machine or equipment and produces the movement of a piston that is responsible for providing the tool with a vibratory axial movement with respect to the controlled linear movement of the support, as You can see in view of figures 1,2 and 3.

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Claims (11)

5 10 fifteen twenty 25 30 35 40 Four. Five fifty 1. Tool holder device attachable to a machine that can cause the device to rotate, the device comprising fastening means (4) for holding a tool (24) and a body (1) comprising a mooring element (5) that allows coupling the device to the machine, where it comprises a mobile part (2) that can move in an axial direction, characterized in that said fastening means (4) are coupled to the mobile part (2), wherein said mobile part ( 2) comprises a chamber (21) that houses a pneumatic mechanism (3) comprising a pneumatic piston (6) that performs a linear movement in at least two directions, so that it can slide axially inside the chamber (21), in wherein said pneumatic mechanism (3) can cause an axial vibratory movement to the mobile part (2), wherein the mobile part (2) further comprises conduction means (8, 23) configured to supply compressed air to said pneumatic mechanism (3 ) through said mooring element (5) and wherein the pneumatic piston (6) further comprises internal ducts (22), said compressed air being transported to said internal ducts (22) that pass through the piston (6) and open in the chamber ( 21) on axially opposite faces of the pneumatic piston (3), thus producing the axial vibratory movement of the pneumatic piston (6). 2. Tool holder device according to claim 1, comprising a regulator (7) that allows varying the amplitude of the axial movement of the mobile part (2). 3. Tool holder device according to claim 2, wherein the regulator (7) comprises a nut (14) which is coupled on the body (1) closing the housing in a first direction according to the axial direction to stop the movement of the mobile part (2) in the first direction, while the body (1) closes the housing in a second direction according to the axial direction and stops the movement, and by which the nut (14) can vary its position in the axial direction by varying the axial length of the housing. 4. Tool holder device according to any of claims 2 or 3, wherein the regulator (7) comprises adjusting means (13) that anchor the nut (14) to the mobile part (2) of the device to fix the position of said nut (14). 5. Tool holder device according to any of the preceding claims, comprising a first buffer stop (10) housed inside the housing to dampen the collision of the mobile part (2) with the body (1). 6. Tool holder device according to any of claims 2 to 5, comprising a second buffer stop (11) in the regulator to dampen the shock of the mobile part (2) with the regulator (7) 7. Tool holder device according to any of the preceding claims, comprising joining means (9) that join the mobile part (2) to the body (1). 8. Tool holder device according to any of the preceding claims, wherein the pneumatic mechanism (3) comprises return means (12). 9. Tool holder device according to any of the preceding claims, comprising a sealing element (15) between the body (1) and the mobile part (2). 10. Tool holder device according to any of the preceding claims, comprising an antifriction element (16) for axial guidance between the mobile part (2) and the body (1). 11. Tool holder device according to any of the preceding claims, wherein the fixed part (1) has through-hole silencer holes (17) made in its surface that allow the device to escape air.